1. Field of the Invention
This invention relates to an image processing apparatus for converting the image of an original into an electrical signal.
2. Description of the Prior Art
In an apparatus for converting the image of an original into an electrical signal and reading the same, unlike a conventional copying apparatus or the like in which light is applied to the image of an original and the reflected image thereof is optically handled, the image of the original is converted into an electrical signal and therefore, by subjecting this signal to various logical processings, accurate automatic recognition of the position at which the original is supported and the size of the original can be accomplished.
For example, an original cover for fixing the original to an original carriage in detecting the original is colored differently from the texture of the original which is black or otherwise colored, preliminary scanning is effected to detect the supported position of the original on the original carriage, the timing at which an original image reading circuit functions is controlled on the basis of the detection information so as to be within the area of the original, and a signal output in which any useless image other than the original has been eliminated is effected. On the other hand, to process a great quantity of originals at a high speed, it is preferable to provide an automatic original feeding mechanism for conveying the originals onto the original carriage. However, if the preliminary scanning for the previously described detection of the state of the original is effected each time an original is fed, there is a disadvantage that a hindrance will occur to the intended high-speed processing.
Also, the shapes of the originals supported on the original carriage are various and it has been difficult to always effect good automatic recognition with respect to these originals.